Vega MINITRAC 31 User manual

Operating Instructions
Radiometric sensor for density
measurement
MINITRAC 31
Four-wire 4 … 20 mA/HART
With SIL qualication
Document ID: 43389

2
Contents
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
Contents
1 About this document ............................................................................................................... 4
1.1 Function ........................................................................................................................... 4
1.2 Target group ..................................................................................................................... 4
1.3 Symbols used................................................................................................................... 4
2 For your safety ......................................................................................................................... 5
2.1 Authorised personnel ....................................................................................................... 5
2.2 Appropriate use................................................................................................................ 5
2.3 Warning about incorrect use............................................................................................. 5
2.4 General safety instructions............................................................................................... 5
2.5 EU conformity................................................................................................................... 6
2.6 NAMUR recommendations .............................................................................................. 6
2.7 Installation and operation in the USA and Canada ........................................................... 6
2.8 Environmental instructions ............................................................................................... 6
3 Product description ................................................................................................................. 7
3.1 Conguration.................................................................................................................... 7
3.2 Principle of operation........................................................................................................ 8
3.3 System limitations ............................................................................................................ 9
3.4 Packaging, transport and storage................................................................................... 10
3.5 Accessories.................................................................................................................... 11
3.6 Corresponding source container.................................................................................... 12
4 Mounting................................................................................................................................. 14
4.1 General instructions ....................................................................................................... 14
4.2 Mounting instructions ..................................................................................................... 15
5 Connecting to power supply................................................................................................. 18
5.1 Preparing the connection ............................................................................................... 18
5.2 Connection - Level detection.......................................................................................... 21
5.3 Connection - Level measurement................................................................................... 24
6 Functional safety (SIL) .......................................................................................................... 26
6.1 Objective........................................................................................................................ 26
6.2 SILqualication.............................................................................................................. 26
6.3 Application area ............................................................................................................. 26
6.4 Safety concept of the parameterization .......................................................................... 27
7 Set up with the display and adjustment module ................................................................ 29
7.1 Insert display and adjustment module............................................................................ 29
7.2 Adjustment system......................................................................................................... 30
7.3 Parameter adjustment - Level measurement.................................................................. 31
7.4 Parameter adjustment - Point level detection.................................................................. 43
7.5 Saving the parameterisation data................................................................................... 54
8 Setup with PACTware............................................................................................................. 56
8.1 Connect the PC.............................................................................................................. 56
8.2 Parameter adjustment with PACTware............................................................................ 57
8.3 Saving the parameterisation data................................................................................... 58
9 Diagnostics and servicing .................................................................................................... 59
9.1 Maintenance .................................................................................................................. 59
9.2 Status messages............................................................................................................ 59

3
Contents
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
9.3 Rectify faults................................................................................................................... 62
9.4 Exchanging the electronics module................................................................................ 64
9.5 Software update ............................................................................................................. 64
9.6 How to proceed if a repair is necessary.......................................................................... 64
10 Dismount................................................................................................................................. 66
10.1 Dismounting steps.......................................................................................................... 66
10.2 Disposal ......................................................................................................................... 66
11 Supplement ............................................................................................................................ 67
11.1 Technical data ................................................................................................................ 67
11.2 Dimensions .................................................................................................................... 71
11.3 Industrial property rights................................................................................................. 74
11.4 Trademark ...................................................................................................................... 74
Safety instructions for Ex areas
TakenoteoftheExspecicsafetyinstructionsforExapplications.
These instructions are attached as documents to each instrument
with Ex approval and are part of the operating instructions.
Editing status: 2021-03-04

4
1 About this document
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
1 About this document
1.1 Function
This instruction provides all the information you need for mounting,
connection and setup as well as important instructions for mainte-
nance,faultrectication,theexchangeofpartsandthesafetyofthe
user. Please read this information before putting the instrument into
operation and keep this manual accessible in the immediate vicinity
of the device.
1.2 Target group
This operating instructions manual is directed to trained personnel.
Thecontentsofthismanualmustbemadeavailabletothequalied
personnel and implemented.
1.3 Symbols used
Document ID
This symbol on the front page of this instruction refers to the Docu-
ment ID. By entering the Document ID on www.vega.com you will
reach the document download.
Information, note, tip: This symbol indicates helpful additional infor-
mation and tips for successful work.
Note: This symbol indicates notes to prevent failures, malfunctions,
damage to devices or plants.
Caution: Non-observance of the information marked with this symbol
may result in personal injury.
Warning: Non-observance of the information marked with this symbol
may result in serious or fatal personal injury.
Danger: Non-observance of the information marked with this symbol
results in serious or fatal personal injury.
Ex applications
This symbol indicates special instructions for Ex applications.
• List
The dot set in front indicates a list with no implied sequence.
1 Sequence of actions
Numbers set in front indicate successive steps in a procedure.
Battery disposal
This symbol indicates special information about the disposal of bat-
teries and accumulators.

5
2 For your safety
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
2 For your safety
2.1 Authorised personnel
All operations described in this documentation must be carried out
onlybytrained,qualiedpersonnelauthorisedbytheplantoperator.
During work on and with the device, the required personal protective
equipment must always be worn.
2.2 Appropriate use
The MINITRAC 31 is a sensor for level measurement and level detec-
tion.
Youcannddetailedinformationabouttheareaofapplicationin
chapter "Product description".
Operational reliability is ensured only if the instrument is properly
usedaccordingtothespecicationsintheoperatinginstructions
manual as well as possible supplementary instructions.
2.3 Warning about incorrect use
Inappropriate or incorrect use of this product can give rise to applica-
tion-specichazards,e.g.vesseloverllthroughincorrectmounting
or adjustment. Damage to property and persons or environmental
contamination can result. Also, the protective characteristics of the
instrument can be impaired.
2.4 General safety instructions
This is a state-of-the-art instrument complying with IEC 61508 and
all prevailing regulations and directives.The instrument must only be
operatedinatechnicallyawlessandreliablecondition.Theoperator
is responsible for the trouble-free operation of the instrument.When
measuring aggressive or corrosive media that can cause a dangerous
situation if the instrument malfunctions, the operator has to implement
suitable measures to make sure the instrument is functioning properly.
The safety instructions in this operating instructions manual, the cor-
responding Safety Manual, the national installation standards as well
as the valid safety regulations and accident prevention rules must be
observed by the user.
For safety and warranty reasons, any invasive work on the device
beyond that described in the operating instructions manual may be
carried out only by personnel authorised by the manufacturer. Arbi-
traryconversionsormodicationsareexplicitlyforbidden.Forsafety
reasons,onlytheaccessoryspeciedbythemanufacturermustbe
used.
To avoid any danger, the safety approval markings and safety tips on
the device must also be observed.

6
2 For your safety
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
2.5 EU conformity
ThedevicefullsthelegalrequirementsoftheapplicableEUdirec-
tives.ByaxingtheCEmarking,weconrmtheconformityofthe
instrument with these directives.
The EU conformity declaration can be found on our homepage.
Electromagnetic compatibility
Instruments in four-wire or Ex-d-ia version are designed for use in an
industrial environment. Nevertheless, electromagnetic interference
from electrical conductors and radiated emissions must be taken into
account, as is usual with class A instruments according to EN 61326-
1.Iftheinstrumentisusedinadierentenvironment,theelectromag-
netic compatibility to other instruments must be ensured by suitable
measures.
2.6 NAMUR recommendations
NAMUR is the automation technology user association in the process
industry in Germany. The published NAMUR recommendations are
acceptedasthestandardineldinstrumentation.
ThedevicefullstherequirementsofthefollowingNAMURrecom-
mendations:
• NE 21 – Electromagnetic compatibility of equipment
• NE 43 – Signal level for fault information from measuring transduc-
ers
• NE53–Compatibilityofelddevicesanddisplay/adjustment
components
• NE107–Self-monitoringanddiagnosisofelddevices
For further information see www.namur.de.
2.7 Installation and operation in the USA and
Canada
This information is only valid for USA and Canada. Hence the follow-
ing text is only available in the English language.
Installations in the US shall comply with the relevant requirements of
the National Electrical Code (ANSI/NFPA 70).
Installations in Canada shall comply with the relevant requirements of
the Canadian Electrical Code.
2.8 Environmental instructions
Protection of the environment is one of our most important duties.
That is why we have introduced an environment management system
with the goal of continuously improving company environmental pro-
tection.Theenvironmentmanagementsystemiscertiedaccording
to DIN EN ISO 14001.
Pleasehelpusfullthisobligationbyobservingtheenvironmental
instructions in this manual:
• Chapter " Packaging, transport and storage"
• Chapter " Disposal"

7
3 Product description
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
3 Product description
3.1 Conguration
Thetypelabelcontainsthemostimportantdataforidenticationand
use of the instrument:
9
9
4
5
3
6
7
8
910
2
1
Fig. 1: Layout of the type label (example)
1 Instrument type
2 Product code
3 Electronics
4 Protection rating
5 Ambient temperature
6 Hardware and software version
7 Order number
8 Serial number of the instrument
9 ID numbers, instrument documentation
10 SILidentication
The type label contains the serial number of the instrument. With it
youcanndthefollowinginstrumentdataonourhomepage:
• Product code (HTML)
• Delivery date (HTML)
• Order-specicinstrumentfeatures(HTML)
• Operating instructions and quick setup guide at the time of ship-
ment (PDF)
• Order-specicsensordataforanelectronicsexchange(XML)
• Testcerticate(PDF)-optional
Move to " www.vega.com"andenterinthesearcheldtheserial
number of your instrument.
Alternatively, you can access the data via your smartphone:
• Download the VEGA Tools app from the " Apple App Store" or the
" Google Play Store"
• Scan the DataMatrix code on the type label of the instrument or
• Enter the serial number manually in the app
This operating instructions manual applies to the following instrument
versions:
Type label
Serial number - Instru-
ment search
Scope of this operating
instructions

8
3 Product description
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
• Hardware from 1.0.6 1)
• Software from 2.1.0
• Hardware from 2.0.0
• Software from 3.0.0
Theinstrumentisavailableindierentelectronicsversions.Eachver-
sioncanbeidentiedviatheproductcodeonthetypelabel:
• StandardelectronicstypePROTRACH.-XX
The scope of delivery encompasses:
• Radiometric sensor
• Documentation
• Bluetooth module (optional)
– This operating instructions manual
– Safety Manual (SIL) PROTRAC series 30 (Document-ID 42961)
– Ex-specic"Safety instructions" (with Ex versions)
– Ifnecessary,furthercerticates
3.2 Principle of operation
The instrument is suitable for applications in liquids in vessels also
underdicultprocessconditions.Thereareapplicationpossibilities
in nearly all areas of industry.
The measured value is detected contactlessly right through the vessel
wall.Neitheraprocessttingnoravesselopeningarerequired.The
instrument is thus ideal for retro installation.
The instrument is various application possibilities. Apart from the level
detection, the MINITRAC 31 can also detect residues.
Electronics versions
Scope of delivery
Application area
1) It is not possible to update the software to 3.0.0. In this case the electronics
module must be exchanged.

9
3 Product description
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
12
Fig. 2: MINITRAC 31 - Application possibilities
1 Level measurement - Residue detection
2 Point level detection
In radiometric measurement, a Caesium-137 or Cobalt-60 isotope
emits focussed gamma rays that are attenuated when penetrating the
vessel wall and the medium. The NaI detector on the opposite side
receives the radiation. The intensity of the radiation depends on the
density of the measured media.The measuring principle has proven
to be very reliable in conjunction with extreme process conditions be-
cause it measures contactlessly from outside through the vessel wall.
The measuring system ensures maximum safety, reliability and plant
availability independent of the medium and its properties.
3.3 System limitations
Thereareseveralmeasuringprinciple-specicfactorswhichcaninu-
ence the measuring result. Keep these factors in mind in order to fully
utilize the capabilities of the instrument with respect to measurement
reliability and non-repeadability.
The implemented radioactive isotope and its activity must be selected
according to the properties of the vessel and the medium.The neces-
sary radioactive activity must be calculated on the basis of the plant
data.
To this end, make use of our planning service for an optimum layout of
the measurement and selection of the isotope.This applies particu-
larly to SIL applications.
Due to the physical properties of the radioactive radiation, the pulse
rateissubjecttoslightuctuations.Setasuitabledampingleveltoget
a stable measured value.
The relation between level and the pulse rate measured by the sensor
is not linear.
Functional principle
Activity of the source
Non-linearity of the pro-
cess value

10
3 Product description
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
Set up a linearization table to get a linear level signal. For precise
mesurement results, make sure when setting up the linearization
tablethattheactualllingheightofthemeasuringpointsisenteredas
exactly as possible.
Externalradiationsourcescaninuencethemeasuredvalue(e.g.
welding joint tests). In safety-relevant applications, the safety function
must be treated as unreliable as long as the external radiation occurs.
If necessary, you must take measures to maintain the safety function.
Make sure during the planning that for the planned application, a
possiblylargedierentofthepulseratewithemptyandfullvesselis
reaced.This applies mainly for products with low density or in vessels
with extremely small diameter.
3.4 Packaging, transport and storage
Your instrument was protected by packaging during transport. Its
capacity to handle normal loads during transport is assured by a test
based on ISO 4180.
The packaging consists of environment-friendly, recyclable card-
board. For special versions, PE foam or PE foil is also used. Dispose
of the packaging material via specialised recycling companies.
Transport must be carried out in due consideration of the notes on the
transport packaging. Nonobservance of these instructions can cause
damage to the device.
The delivery must be checked for completeness and possible transit
damage immediately at receipt. Ascertained transit damage or con-
cealed defects must be appropriately dealt with.
Up to the time of installation, the packages must be left closed and
stored according to the orientation and storage markings on the
outside.
Unless otherwise indicated, the packages must be stored only under
the following conditions:
• Not in the open
• Dry and dust free
• Not exposed to corrosive media
• Protected against solar radiation
• Avoiding mechanical shock and vibration
• Storage and transport temperature see chapter " Supplement -
Technical data - Ambient conditions"
• Relative humidity 20 … 85 %
With instrument weights of more than 18 kg (39.68 lbs) suitable and
approved equipment must be used for lifting and carrying.
External radiation
Span
Packaging
Transport
Transport inspection
Storage
Storage and transport
temperature
Lifting and carrying

11
3 Product description
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
3.5 Accessories
The display and adjustment module is used for measured value indi-
cation, adjustment and diagnosis.
The integrated Bluetooth module (optional) enables wireless adjust-
ment via standard adjustment devices.
The interface adapter VEGACONNECT enables the connection of
communication-capable instruments to the USB interface of a PC.
The VEGADIS 81 is an external display and adjustment unit for VEGA
plics®sensors.
VEGADIS 82 is suitable for measured value indication and adjustment
of sensors with HART protocol. It is looped into the 4 … 20 mA/HART
signal cable.
The VEGADIS 62 is suitable for measured value indication of sensors.
It is looped into the 4 … 20 mA/HART signal cable.
The electronics module PT30… is a replacement part for radiometric
sensors MINITRAC 31.
It is located in the large electronics and connection compartment.
The electronics module can only be exchanged by VEGA service
technician.
The supplementary electronics module PROTRAC.ZE… is a replace-
ment part for radiometric sensors MINITRAC 31.
It is located in the lateral adjustment and connection compartment.
Brackets and special mounting accessories are available for mount-
ing the MINITRAC 31.
For mounting on pipelines, there are corresponding clamp brackets.
Contactoursalessta.
The radiometric sensor has temperature limits which must not be
exceeded. In case the max. permissible temperature is exceeded,
faulty measurements and a permanent damage of the sensor can be
caused.
You have several possibilities to avoid too high ambient temperatures:
Passive sun shade
Direct sun increases the temperature on the sensor by 20 °K.The
bestpossibilitytoprotectthesensoragainsttheeectsofdirectsun
is a suitable roof structure.
Ifthisisnotpossibleoronlywithgreateort,thenyoucanusethe
passive sun shade. The passive sun shade consists of a housing sun
shade and a sun protection hose and can reduce the sensor tempera-
ture by 10 °K.
PLICSCOM
VEGACONNECT
VEGADIS 81
VEGADIS 82
External indicating unit
Electronics module -
PT30
Supplementary electron-
ics module - PROTRAC.
ZE
Mounting accessories
Device cooling

12
3 Product description
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
Air cooling
For ambient temperatures up to +80 °C you can use an air cooling.
The cooling air is generated with vortex coolers. Please check if suf-
cientcompressedairisavailable.Youcanndfurtherinformation
in the supplementary instructions of the air cooling. The air cooling
cannotberetrotted.
Water cooling
For ambient temperatures up to +100 °C you can use a water cool-
ing.Pleasecheckifsucientcooledwaterisavailable.Youcannd
further information in the supplementary instructions of the water
cooling.Thewatercoolingcannotberetrotted.
3.6 Corresponding source container
A radioactive isotope in a suitable source holder is the prerequisite for
a radiometric measurement setup.
The handling of radioactive substances is regulated by law.The radia-
tion protection rules of the country in which the system is operated
applyrstandforemost.
In Germany, for example, the current radiation protection ordinance
(StrlSchV) based on the Atomic Energy Law (AtG) applies.
The following points are important for measurement with radiometric
methods:
A handling permit is required for operation of a system using gamma
rays.Thispermitisissuedbytherespectivegovernmentoceorthe
responsibleauthority(inGermany,forexample,ocesforenviron-
mental protection, trade supervisory boards, etc.)
Youcanndfurtherinstructionsintheoperatinginstructionsmanual
of the source container.
When handling radioactive sources, unnecessary radiation exposure
must be avoided. An unavoidable radiation exposure must be kept as
low as possible.Take note of the following three important measures:
1 2 3
Fig. 3: Measures for protection against radioactive radiation
1 Shielding
2 Time
3 Distance
Shielding: Provide good shielding between the source and your-
self as well as all other persons. Special source containers (e.g.
Handling permit
General instructions for
radiation protection

13
3 Product description
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
VEGASOURCE) as well as all materials with high density (e.g. lead,
iron,concrete,etc.)provideeectiveshielding.
Time: Stay as short a time as possible in radiation exposed areas.
Distance:Your distance to the source should be as large as possible.
The local dose rate of the radiation decreases in proportion to the
square of the distance to the radiation source.
Theplantoperatormustappointaradiationsafetyocerwiththe
necessary expert knowledge. He is responsible for ensuring that the
radiation protection ordinance is complied with and for implementing
all radiation protection measures.
Control areas are areas in which the local dose rate exceeds a certain
value.Onlypersonswhoundergoocialdosemonitoringareallowed
intothesecontrolareas.Youcanndtherespectivelyvalidlimitvalues
for control areas in the guideline of the respective authority (in Ger-
many, for example, the radiation protection ordinance).
We are at your disposal for further information concerning radiation
protection and regulations in other countries.
Radiationsafetyocer
Control area

14
4 Mounting
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
4 Mounting
4.1 General instructions
The source container is part of the measuring system. In case the
source container is already equipped with an active isotope, the
source container must be locked before mounting.
Danger:
Before mounting; make sure that the source is securely closed. Use
a padlock to secure the source container in the closed condition and
prevent it from being inadvertently opened.
Protect your instrument against moisture ingress through the following
measures:
• Use a suitable connection cable (see chapter " Connecting to
power supply")
• Tighten the cable gland or plug connector
• Lead the connection cable downward in front of the cable entry or
plug connector
This applies mainly to outdoor installations, in areas where high
humidity is expected (e.g. through cleaning processes) and on cooled
or heated vessels.
Note:
Make sure that during installation or maintenance no moisture or dirt
can get inside the instrument.
To maintain the housing protection, make sure that the housing lid is
closed during operation and locked, if necessary.
Note:
For safety reasons, the instrument must only be operated within the
permissibleprocessconditions.Youcannddetailedinformationon
the process conditions in chapter " Technical data" of the operating
instructions or on the type label.
Hence make sure before mounting that all parts of the instrument ex-
posed to the process are suitable for the existing process conditions.
These are mainly:
• Active measuring component
• Processtting
• Process seal
Process conditions in particular are:
• Process pressure
• Process temperature
• Chemical properties of the medium
• Abrasionandmechanicalinuences
Switchosource
Protection against mois-
ture
Process conditions

15
4 Mounting
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
Metric threads
In the case of instrument housings with metric thread, the cable
glands are screwed in at the factory. They are sealed with plastic
plugs as transport protection.
You have to remove these plugs before electrical connection.
NPT thread
In the case of instrument housings with self-sealing NPT threads, it is
not possible to have the cable entries screwed in at the factory.The
free openings for the cable glands are therefore covered with red dust
protection caps as transport protection.
Prior to setup you have to replace these protective caps with ap-
proved cable glands or close the openings with suitable blind plugs.
The suitable cable glands and blind plugs come with the instrument.
4.2 Mounting instructions
Note:
During the planning, our specialists will analyse the conditions of the
measurement loop to dimension the isotope accordingly.
You get a "Source Sizing" document specifying the required source
activity and containing all relevant mounting information for your
measuring point.
You must follow the instructions in this "Source Sizing" document in
addition to the following mounting instructions.
The following mounting information is applicable as long as there is
nothingelsespeciedinthe"SourceSizing"document.
Youcanndinformationonprotectivebarriersandthemounting
of the corresponding source container in the operating instructions
manual of the source container, e.g. VEGASOURCE.
You can mount the MINITRAC 31 in any position. If you have ordered
your instrument with a lead cover as a protection against ambient
radiation(optionally),thethesensorisshieldedlaterallyagainstX-ray
radiation. In this case, the radiation can only penetrate frontally.
Fasten the sensors in such a way that they cannot fall out of the
holder.
Direct the exit angle of the source container to the MINITRAC 31.
Mount the source container as close as possible to the vessel. If there
are gaps, secure the area with a safety fence and protective grating
so that no one can reach into the dangerous area.
Point level detection
For level detection, the sensor is generally mounted horizontally at the
height of the requested limit level. Make sure that there are no struts
or reinforcements at this position in the vessel.
Direct the exit beam of the source container exactly towards the
measuring range of MINITRAC 31.
Cable glands
Installation position

16
4 Mounting
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
3
2
1
Fig. 4: Mounting position - level detection
1 Horizontal mounting
2 Vertical mounting
3 Mounting horizontally, at right angles to container
Level measurement - Residue detection
The MINITRAC 31 can be used for residue detection, e.g. in storage
tanks for high-cost liquids. For this purpose, the instrument must be
mounted at the lowest point of the vessel.

17
4 Mounting
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
Fig. 5: Level measurement - Residue detection on a storage tank
If the max. ambient temperature is exceeded, you must take suitable
measures to protect the instrument against overheating.
You can protect the instrument by providing a suitable insulation
against the heat or mounting the instrument further away from the
heat source.
Make sure these measures are taken into account already in the plan-
ning stage. If you want to carry out such measures later on, contact
our specialists to ensure that the accuracy of the application is not
impaired.
Ifthesemeasuresarenotsucienttomaintainthemax.ambient
temperature, you could consider using the water or air cooling system
weoerforMINITRAC31.
The cooling system must also be included in the calculations for the
measuring point. Contact our specialists regarding the dimensioning
of the cooling.
Protection against heat

18
5 Connecting to power supply
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
5 Connecting to power supply
5.1 Preparing the connection
Always keep in mind the following safety instructions:
• The electrical connection must only be carried out by trained,
qualiedpersonnelauthorisedbytheplantoperator.
• If overvoltage surges are expected, overvoltage arresters should
be installed.
Warning:
Only connect or disconnect in de-energized state.
In this case, the instrument is designed in protection class I.To main-
tain this protection class, it is absolutely necessary that the ground
conductor be connected to the internal ground terminal.Take note of
the national installation regulations.
Supply voltage and current output are carried on separate connection
cables if reliable separation is required. The supply voltage range can
dierdependingontheinstrumentversion.
Thedataforpowersupplyarespeciedinchapter"Technical data".
General requirements
• Make sure that the cable used has the required temperature resist-
anceandresafetyformax.occurringambienttemperature
• Use cable with round cross section for instruments with housing
andcablegland.Toensurethesealeectofthecablegland(IP
protectionrating),ndoutwhichcableouterdiameterthecable
gland is suitable for.
• Useacableglandttingthecablediameter.
• Unusedcableglandsdonotoersucientprotectionagainst
moisture and must be replaced by blind plugs.
Voltage supply
For power supply, an approved, three-wire installation cable with PE
conductor is required.
Signal cable
The 4 … 20 mA current output is connected with standard two-wire
cable without shielding. If electromagnetic interference is expected
which is above the test values of EN 61326-1 for industrial areas,
shielded cable should be used.
Metric threads
In the case of instrument housings with metric thread, the cable
glands are screwed in at the factory. They are sealed with plastic
plugs as transport protection.
You have to remove these plugs before electrical connection.
NPT thread
In the case of instrument housings with self-sealing NPT threads, it is
not possible to have the cable entries screwed in at the factory.The
Safety instructions
Voltage supply via mains
voltage
Select connection cable
Cable glands

19
5 Connecting to power supply
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
free openings for the cable glands are therefore covered with red dust
protection caps as transport protection.
Before setup you have to replace these protective caps with approved
cable glands or close the openings with suitable blind plugs. Unused
cableglandsdonotprovidesucientprotectionagainstmoistureand
must be replaced with blind plugs.
The suitable cable glands and blind plugs come with the instrument.
If shielded cable is required, connect the cable screen on both ends
to ground potential. In the sensor, the screen must be connected
directly to the internal ground terminal.The ground terminal on the
outside of the housing must be connected to the potential equalisa-
tion (low impedance).
If potential equalisation currents are expected, the connection on the
processing side must be made via a ceramic capacitor (e. g. 1 nF,
1500 V). The low-frequency potential equalisation currents are thus
suppressed,buttheprotectiveeectagainsthighfrequencyinterfer-
ence signals remains.
Warning:
Signicantpotentialdierencesexistinsidegalvanizationplantsas
well as on vessels with cathodic corrosion protection. Considerable
equalisationcurrentscanowoverthecablescreenifthescreenis
grounded on both ends.
To avoid this, the cable screen in such applications must be con-
nected only on one end to ground potential in the switching cabinet.
The cable screen must not be connected to the inner ground terminal
in the sensor and the outer ground terminal on the housing must not
be connected to potential equalization!
Information:
The metal parts of the instrument are conductively connected with
the inner and outer ground terminal on the housing.This connection
is either a direct metallic connection or, in case of instruments with
external electronics, a connection via the screen of the special con-
nection cable.
Youcanndspecicationsonthepotentialconnectionsinsidethe
instrument in chapter "Technical data".
The voltage supply and signal output are connected via the spring-
loaded terminals in the housing.
Connection to the display and adjustment module or to the interface
adapter is carried out via contact pins in the housing.
Proceed as follows:
The procedure applies to instruments without explosion protection.
1. Unscrew the big housing cover
2. Loosen compression nut of the cable gland and remove blind
plug
Cable screening and
grounding
Connection technology
Connection procedure

20
5 Connecting to power supply
MINITRAC 31 • Four-wire 4 … 20 mA/HART
43389-EN-210311
3. Remove approx. 10 cm (4 in) of the cable mantle, strip approx.
1 cm (0.4 in) of insulation from the ends of the individual wires
4. Insert the cable into the sensor through the cable entry
1
Fig. 6: Connection steps 4 and 5
1 Locking of the terminal blocks
5. Insertasmallslottedscrewdriverrmlyintotherectangularlock
openings of the respective connection terminal
6. Insert the wire ends into the round openings of the terminals ac-
cording to the wiring plan
Information:
Solidcoresaswellasexiblecoreswithcableendsleevesare
inserteddirectlyintotheterminalopenings.Incaseofexiblecores
without end sleeves, press the rectangular lock opening with a small
screwdriver; the terminal opening is freed. When the screwdriver is
released, the terminal opening closes again.
7. Check the hold of the wires in the terminals by lightly pulling on
them
Toloosenaline,insertasmallslottedscrewdriverrmlyintothe
rectangular lock opening according to the illustration
8. Connect the shielding to the internal ground terminal, connect the
external ground terminal to potential equalisation
9. Tighten the compression nut of the cable entry gland. The seal
ring must completely encircle the cable
10. Screw the housing lid back on
Theelectricalconnectionisnished.
Information:
The terminal blocks are pluggable and can be detached from the
electronics.To do this, loosen the two lateral locking levers of the
terminal block with a small screwdriver. When loosening the locking,